High power Ka-Band solid-state power amplifiers (SSPA) are generally required for communications from deep space to Earth. The highest power Ka-Band (31.8 to 32.3 GHz) SSPA to have been used in space to date had a power output of 2.6 watts and an overall efficiency of 14.3 percent. This SSPA was built around discrete Gallium Arsenide (GaAs) Pseudomorphic High Electron Mobility Transistor (pHEMT) devices and was implemented onboard Deep Space One spacecraft. Since that time, monolithic microwave integrated circuit (MMIC) power amplifier (PA) technology has advanced. The state-of-the-art (SOA) GaAs pHEMT-based MMICs are generally capable of delivering radio frequency (RF) power in a range from 3 watts with a power added efficiency (PAE) of 32 percent to 6 watts with a PAE of 26 percent, at Ka-Band frequencies. To achieve power levels higher than 6 watts, the output of several MMIC PAs must be combined using a power combiner.